Such a chopper converter may be a controlled two-port electrical circuit comprising a first pair of positive and negative terminals and a second pair of positive and negative terminals. The first and second negative terminals may be connected together by a first determined circuit branch. Similarly, the first and second positive terminals may be connected together by a second determined circuit branch which includes an inductor forming an energy reservoir. The converter may further comprise chopper means comprising at least one controlled switch which is switched OFF and ON with a determined duty ratio under the control of a management unit.
Such a circuit may be capable of delivering direct and/or quasi-direct electric current between the first pair of positive and negative terminals at a determined voltage, referred to as the “output” voltage, when a determined voltage, referred to as the “input” voltage, is applied between the second pair of positive and negative terminals, or vice versa.
The converter is said to be non-isolated in the sense that it comprises the first and second circuit branches respectively interconnecting the first and second negative terminals and the first and second positive terminals. Such a converter is contrasted with an isolated converter in which the first pair of terminals is isolated from the second pair of terminals.
In order to reduce the size of the components making up the converter, while delivering sufficient power to feed various items of equipment, it is known, in particular from document U.S. Pat. No. 6,275,958, to implement a multicellular converter comprising a series of cells connected in parallel. When a cell is faulty, it is also known from that document to isolate the faulty cell by means of two protection switches formed by metal oxide semiconductor (MOS) transistors disposed one on a high-voltage network side and the other on a low-voltage network side.
Those transistors operate as controlled switches which are ON in normal operation and which are OFF when malfunction is detected.
It follows that in normal operation, the components that are dedicated to the protection function give rise to static consumption of power which, depending on circumstances, can lie in the range 0.5% to 2.0% of the static consumption of the circuit as a whole.
Furthermore, the presence of those protection components leads to an increase in the size of the electrical circuit, to a lengthening and greater complexity in the manufacturing method, and finally to a significant increase in the cost of the circuit.